Engorged Deer Tick vs. Engorged Dog Tick: How to Tell the Difference Between Them


Written by Mitchelle Morgan

Updated: June 26, 2023

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Tick bites are common, and with the rising incidences of Lyme disease, engorged ticks are a concern. But not all ticks are carriers of Lyme disease, and it is essential to know their differences.

In the United States, there are 80 identified species of ticks. The most common ticks you may encounter are the deer tick, the dog tick (American or brown), or the lone star tick. Ticks are known carriers of disease-causing pathogens, but knowing the type of tick species can help determine the risk of infection in humans or pets.

However, engorged ticks can look similar to the untrained eye. So, it’s essential to differentiate between the species, as ticks can spread other diseases besides Lyme.

Here is a guide to help you identify the differences and similarities between engorged deer and dog ticks. We will also guide you on how to prevent tick bites, how to remove an attached tick, and what to do when you get a tick bite.

What are Ticks?

Ticks are external parasites that suck blood from their hosts. They belong to the Arachnid class of Arthropods, including scorpions, mites, and spiders. Ticks are small with two main body parts. They have four pairs of legs, are wingless, and have no antennae.

A wet deer tick crawling on natural dewy leaf with water drops.

A deer tick has four pairs of legs, each with seven segments and claws at the tips.

Physical characteristics such as color patterns, appearance, and size among ticks vary according to species and gender. Ticks also change in appearance after feeding, and their bodies increase in size and shape after ingesting the host’s blood.

Here is a look at some common traits of ticks:


  • Four pairs of legs, each with seven segments and having claws at the tips
  • Wingless
  • No antennae
  • A small head is known as the capitulum
  • A projecting set of mouthparts that has three main parts – chelicerae, palps, and hypostome
  • An oval body called the idiosoma
  • A darker, hardened plate on the back called the scutum

The scutum on ticks helps in identifying females from males. On a female tick, the scutum covers about 1/3 of its back; on males, it covers almost the whole back. Most ticks also have distinct color patterns on their scutum, which help identify individual species.  


  • Adult ticks range between 2 -6 mm long
  • Nymphs range between 1 – 2 mm long

After feeding, female ticks become engorged, increasing their size several times. They enlarge to approximately 10 -15 mm. Male ticks don’t grow in size after feeding as they don’t become engorged.


From the top, ticks are oval or teardrop shaped. On the side view, they are flat before feeding. After feeding, a female tick bears a coffee bean shape once engorged.


Color patterns of ticks vary depending on the species. Many ticks will have a black, gray, yellow, reddish-brown, or brown color.

What is an Engorged Tick?

Ticks survive by feeding off blood from vertebrates starting early in their lives. A tick has four stages in life, egg, larva nymph, and adult. Nymphs attach to animals but don’t suck as much blood as an adult female.

Tick nymphs, like rodents, may seek smaller animals closer to their habitat in the early stages. They may also transfer from one animal to another. You can see an engorged tick across many hosts, including pets, wildlife, and farm animals. 

Dog Tick sucking the blood of dogs and insect spreading pathogens.

This dog tick is engorged after sucking the blood of its victim.

An engorged tick is an adult female of any tick species seen too late on a host. At this stage, the tick will be several times larger due to more days of sucking. Although male ticks also suck blood, they don’t stick to the host for long, dropping off in search of a mate. Females linger longer to gather enough food to support egg laying.

A partially engorged tick looks big, roundish, and wrinkly, while an unengorged tick has a small, flat oval shape.

For a tick to transmit pathogens, a tick needs to suck on a host for up to three days. You can easily spot ticks on your loved ones and pets early before becoming engorged. So, a thorough outdoor clean-up, regular check-ups, protective measures, and more will help keep you safe.

Difference Between an Engorged Deer Tick vs. Engorged Dog Tick

Deer and dog ticks are the same species, but their characteristics differ.

TraitDeer tickAmerican dog tickBrown dog tick
Adult ColorBrown, orange with dark legsReddish-brown legs match the bodyReddish-brown or yellowish-brown legs match the body
Engorged colorGreen-silverGray or dark redGreen yellow
Scutum markingsNoneWhitish spotsNone
Female scutumSmall and darkSmall dark with white markingsSmall and reddish-brown
SizeNymphs are the size of a poppy seed. Unfed adults are like sesame seedsUnfed adults equal the size of an apple seedUnfed adults equal the size of a sesame seed
LocationMainly in the Eastern U.S. in proximity to white-tailed deer habitatsMost common east of the Rocky Mountains and alongThe most widespread tick globally
Where you encounter themOvergrown areas, including forests and grasslands -on pets who frequent outdoorsNatural areas free of tree cover -On trails -Dog kennels and other areas where pets play or sleepWithin homesteads -Natural areas free of tree cover -On trails -Dog kennels
When activeFrom late spring through early fall -more rampant in May and AugustApril through AugustVaries according to region
Potential health issuesLyme disease, Anaplasmosis, Babesiosis, Ehrlichiosis    Rocky Mountain spotted fever, Ehrlichiosis, Tularemia, Tick paralysisRocky Mountain spotted fever, Ehrlichiosis  

How to Identify an Engorged Deer Tick?

The deer tick (Ixodes scapularis), also known as the black-legged tick, is one of the smallest ticks found in forests, shrubs, or tall meadows in the United States. A fully grown adult reaches only up to 3 mm long.

They are common in the eastern United States. On the west coast lives their closest cousin, the western black-legged tick. They are highly present in regions where white-tailed deer roam, their primary host choice.

They have a distinct orange-red color on their body and wear a black scutum. The species has dark legs that match their scuta.

Deer ticks have a life span of 2-3 years, which varies according to the environment. Adult females lay up to 4,000 eggs once in early spring before their death. The eggs incubate and hatch into larvae in late summer.

Larvae attach to small rodents to feed. An engorged deer tick larva remains dormant during fall using the excess stored blood feed as they evolve into a nymph.

The deer tick nymphs are mainly active in spring and more rampant in May and August. They seek new hosts and can infect their host as they suck blood with disease-causing pathogens if infected.

Deer tick nymphs are the primary transmitters of Borrelia burgdoreri and may go unnoticed due to their small size of 1-1.5 mm long. Engorged nymphs molt into adults during fall.

As deer tick nymphs metamorphose into female adults, they quest for other hosts for feed in preparation for mating. Only female deer ticks become engorged. Male ticks feed less and are always busy in search of mates. After mating, a male tick dies, just like a female after it lays eggs.

Deer Tick Appearance

Deer ticks have a brown-orange and black color and have an oval body that is flat before feeding. Their mouthparts are long and hexagonal. A female scutum is small and near the head, while a dark scuta almost covers the male dorsal.

Female deer ticks are more prominent than males and have a reddish color. Males have a dark brown or black color. Deer ticks lack other markings on their body like many other tick species.

An adult female engorged deer tick may appear dull green, grayish, or brownish with black legs matching its scuta.

The deer tick is the only species known to transmit Borrelia mayoni and B. burgdorferi, the bacteria that cause Lyme disease. The ticks also transmit other infections that cause disease in humans, dogs, and cats, including:

  • Anaplasmosis
  • Babesiosis
  • Ehrlichiosis

How to Identify an Engorged Dog Tick?

The typical American dog tick (Dermacentor variabilis), the wood tick, is larger than the deer tick. An adult can reach lengths of up to 5 mm in size.

A distinctive feature of these ticks is the white markings on their backs. The white markings also help to separate gender. Males have the markings all over their backs, but on females; they only appear on their scuta.

American dog ticks have the same biological cycle as deer ticks. The main difference is that adult wood ticks are most active in May and June, while the black-legged ticks peak in October and November.

American Dog Tick Appearance

The species nymphs have a lighter color (yellowish) before feeding and average 0.9 mm long. Adults are almost the same size as an apple seed with a reddish-brown color. They are primarily present along the west coast and east of the Rocky Mountains.

The females have a short scutum with white markings. The scutum on male American dog ticks covers most of the dorsal surface bearing the same white markings.

An engorged female American dog tick looks grayish-green in color and spots a scutum near the head with white markings.

The difference between engorged deer and American dog ticks is their scutum and feet.

  • Deer tick – black legs with a black scutum
  • American dog tick – reddish-brown legs and off-white scutum

Although the American dog ticks do not carry the Lyme causing bacteria, they can transmit other diseases to both cats and dogs:

  • Rocky Mountain spotted fever
  • Tularemia
  • Tick paralysis

How to Identify an Engorged Brown Dog Tick?

The brown dog tick (Rhipicephalus sanguineus) is populous and widespread worldwide. They are smaller than the American dog ticks and almost equal to a sesame seed.

They are reddish-brown and have reddish legs. Adult females and males are almost equal in size and may look alike, but males have a darker color.

Dogs are the favorite hosts of brown dog ticks, though they bite and suck on other animals, including cats and humans.

Brown Dog Tick Appearance

Unfed adult brown dog ticks have a reddish-brown color and no markings. Their mouthparts are shorter compared to deer ticks.

Engorged brown dog ticks have a greenish or yellowish-green color. They have reddish legs, and their scutum is brown. By looking at the parasite body and leg colors, you can quickly tell the difference between engorged deer ticks and engorged brown dog ticks.

The brown dog ticks are not carriers of Lyme disease but can transmit ehrlichiosis, and Rocky Mountain spotted fever to dogs.

What to Do if You Find an Engorged Tick on Your Pet

Ticks are prevalent in the United States, and there is a chance of experiencing a tick bite either personally, on your children, or pets.

Not all ticks transmit disease, and early sighting and removal reduce the chances of disease transmission.

A tick can bite on your skin without feeling, only to see it later already attached. The situation is worse on the parts you can’t see, like your back or scalp. You may feel it as the tick engorges long after the bite in such places.

Steps of Removing an Engorged Tick from the Skin

 It would help to have tweezers, gloves, and disinfectant when removing a tick from the skin.

  • Aim to grab the tick on its head closest to the skin. Avoid the tick abdomen. You will create a mess by bursting its belly, which is full of blood.
  • Pull the tick up gently from the skin without jerking or twisting.
  • Check and ensure all parts of the tick are removed.
  • Disinfect the bitten area.
  • Keep a close observation, and if symptoms manifest following the bite, seek medical attention or take your pet to the vet.

Lyme Disease Symptoms in Human

If you’re developing a concerning rash on the area, and have flu-like symptoms within several weeks after the bite, consult your doctor immediately.

You may also experience these signs without ever noticing a tick on your skin. In such a case, seek a professional to determine the cause because even other biting creatures can have the same effect.

One tell-tale sign of Lyme disease is a bulls-eye rash originating from the point of the tick bite. Such a rash may appear after the tick has fallen off without you even noticing it biting your skin.

Some tick bites may start to ooze or get redder, a sign of infection that needs medical attention.

Lyme disease, if detected early, is treatable using oral antibiotics.

Lyme Disease Symptoms in Dogs

Although some canine friends may fail to show symptoms of Lyme disease infection, these signs may manifest in some dogs after two to five months.

Symptoms of Lyme Disease in Dogs

  • Fever
  • Difficult breathing
  • Lack of appetite
  • Fatigue
  • Joint inflammation
  • Lameness
  • Lethargy
  • Swollen lymph nodes

To determine Lyme disease in dogs, vets use a differential diagnosis since the condition has similar symptoms to anaplasmosis.

How to Prevent Tick Bites

You can use several precautions to protect yourself and loved ones from tick bites:

  • Learn what ticks look like and their habitats.
  • Treat pets with vet-standard tick and flea preventatives.
  • Wear pants, long sleeves, head coverings, and closed-toe shoes to cover most of your body outdoors.
  • Use bug repellents when outdoors.
  • A void bushy area and stay on trails
  • Thoroughly check for ticks on your body after spending time in nature.
  • Have a shower after your outdoor activity.
  • Conduct regular tick checks on your pets.
  • Clean your pets’ kennel, beds, and other areas where they spend their time.
  • If your property is near a bushy area, make a barrier to prevent ticks from crawling inside. You can achieve this by having a barren strip along the property border.

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About the Author

Mitchelle is a content writer who loves nature. She loves writing about animals and plants. In her free time, she enjoys hiking and going for nature walks.

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